119 research outputs found
Improving Physical Layer Security of Cellular Networks Using Full-Duplex Jamming Relay-Aided D2D Communications
This paper investigates the physical layer security and data transmission in cellular networks with inband underlay Device-to-Device (D2D) communications, where there is no direct link between D2D users. We propose to apply full-duplex (FD) transmission and dual antenna selection at the D2D relay node. The relay node can simultaneously act as a friendly jammer to improve the secrecy performance of the cellular network while enhancing the D2D communication data transmission. This is an appealing and practical scheme where spectrum sharing is beneficial for the D2D and cellular networks in terms of reliability enhancement and security provisioning, respectively. The practical scenario, where the eavesdropper is passive, is considered. The eavesdropper uses either selection combining or maximal ratio combining to combine the wiretapped signals of the cellular network. The secrecy performance of the cellular network is analyzed, and closed-form expressions for the secrecy outage probability and the probability of non-zero secrecy capacity are derived. We show that increasing the number of FD jamming antennas enhances the secrecy performance of the cellular network. A closed-form expression of the D2D outage probability is also provided. Simulation and numerical results are provided to verify the efficiency of the proposed scheme and to validate the accuracy of the derived expressions
Physical layer security in 5G and beyond wireless networks enabling technologies
Information security has always been a critical concern for wireless communications due
to the broadcast nature of the open wireless medium. Commonly, security relies on cryptographic
encryption techniques at higher layers to ensure information security. However,
traditional cryptographic methods may be inadequate or inappropriate due to novel improvements
in the computational power of devices and optimization approaches. Therefore,
supplementary techniques are required to secure the transmission data. Physical layer
security (PLS) can improve the security of wireless communications by exploiting the characteristics
of wireless channels. Therefore, we study the PLS performance in the fifth generation
(5G) and beyond wireless networks enabling technologies in this thesis. The thesis
consists of three main parts.
In the first part, the PLS design and analysis for Device-to-Device (D2D) communication
is carried out for several scenarios. More specifically, in this part, we study the
underlay relay-aided D2D communications to improve the PLS of the cellular network. We
propose a cooperative scheme, whereby the D2D pair, in return for being allowed to share
the spectrum band of the cellular network, serves as a friendly jammer using full-duplex
(FD) and half-duplex (HD) transmissions and relay selection to degrade the wiretapped
signal at an eavesdropper. This part aims to show that spectrum sharing is advantageous
for both D2D communications and cellular networks concerning reliability and robustness
for the former and PLS enhancement for the latter. Closed-form expressions for the D2D
outage probability, the secrecy outage probability (SOP), and the probability of non-zero
secrecy capacity (PNSC) are derived to assess the proposed cooperative system model. The
results show enhancing the robustness and reliability of D2D communication while simultaneously
improving the cellular network’s PLS by generating jamming signals towards the
eavesdropper. Furthermore, intensive Monte-Carlo simulations and numerical results are
provided to verify the efficiency of the proposed schemes and validate the derived expressions’
accuracy.
In the second part, we consider a secure underlay cognitive radio (CR) network in the
presence of a primary passive eavesdropper. Herein, a secondary multi-antenna full-duplex
destination node acts as a jammer to the primary eavesdropper to improve the PLS of the
primary network. In return for this favor, the energy-constrained secondary source gets
access to the primary network to transmit its information so long as the interference to the
latter is below a certain level. As revealed in our analysis and simulation, the reliability and
robustness of the CR network are improved, while the security level of the primary network
is enhanced concurrently.
Finally, we investigate the PLS design and analysis of reconfigurable intelligent surface
(RIS)-aided wireless communication systems in an inband underlay D2D communication
and the CR network. An RIS is used to adjust its reflecting elements to enhance the data
transmission while improving the PLS concurrently. Furthermore, we investigate the design
of active elements in RIS to overcome the double-fading problem introduced in the RISaided
link in a wireless communications system. Towards this end, each active RIS element
amplifies the reflected incident signal rather than only reflecting it as done in passive RIS
modules. As revealed in our analysis and simulation, the use of active elements leads to a
drastic reduction in the size of RIS to achieve a given performance level. Furthermore, a
practical design for active RIS is proposed
A Survey of Physical Layer Security Techniques for 5G Wireless Networks and Challenges Ahead
Physical layer security which safeguards data confidentiality based on the
information-theoretic approaches has received significant research interest
recently. The key idea behind physical layer security is to utilize the
intrinsic randomness of the transmission channel to guarantee the security in
physical layer. The evolution towards 5G wireless communications poses new
challenges for physical layer security research. This paper provides a latest
survey of the physical layer security research on various promising 5G
technologies, including physical layer security coding, massive multiple-input
multiple-output, millimeter wave communications, heterogeneous networks,
non-orthogonal multiple access, full duplex technology, etc. Technical
challenges which remain unresolved at the time of writing are summarized and
the future trends of physical layer security in 5G and beyond are discussed.Comment: To appear in IEEE Journal on Selected Areas in Communication
Physical-Layer Security with Full-Duplex Transceivers and Multiuser Receiver at Eve
Full-duplex communication enables simultaneous transmission from both ends of a communication link, thereby promising significant performance gains. Generally, it has been shown that the throughput and delay gains of full-duplex communication are somewhat limited in realistic network settings, leading researchers to study other possible applications that can accord higher gains. The potential of full-duplex communication in improving the physical-layer security of a communication link is investigated in this contribution. We specifically present a thorough analysis of the achievable ergodic secrecy rate and the secrecy degrees of freedom with full-duplex communication in the presence of a half-duplex eavesdropper node, with both single-user decoding and multi-user decoding capabilities. For the latter case, an eavesdropper with successive interference cancellation and joint decoding capabilities is assumed. Irrespective of the eavesdropper capabilities and channel strengths, the ergodic secrecy rate with full-duplex communication is found to grow linearly with the log of the direct channel signal-to-noise-ratio (SNR) as opposed to the flattened out secrecy rate with conventional half-duplex communication. Consequently, the secrecy degrees of freedom with full-duplex is shown to be two as opposed to that of zero in half-duplex mode
Relaying in the Internet of Things (IoT): A Survey
The deployment of relays between Internet of Things (IoT) end devices and gateways can improve link quality. In cellular-based IoT, relays have the potential to reduce base station overload. The energy expended in single-hop long-range communication can be reduced if relays listen to transmissions of end devices and forward these observations to gateways. However, incorporating relays into IoT networks faces some challenges. IoT end devices are designed primarily for uplink communication of small-sized observations toward the network; hence, opportunistically using end devices as relays needs a redesign of both the medium access control (MAC) layer protocol of such end devices and possible addition of new communication interfaces. Additionally, the wake-up time of IoT end devices needs to be synchronized with that of the relays. For cellular-based IoT, the possibility of using infrastructure relays exists, and noncellular IoT networks can leverage the presence of mobile devices for relaying, for example, in remote healthcare. However, the latter presents problems of incentivizing relay participation and managing the mobility of relays. Furthermore, although relays can increase the lifetime of IoT networks, deploying relays implies the need for additional batteries to power them. This can erode the energy efficiency gain that relays offer. Therefore, designing relay-assisted IoT networks that provide acceptable trade-offs is key, and this goes beyond adding an extra transmit RF chain to a relay-enabled IoT end device. There has been increasing research interest in IoT relaying, as demonstrated in the available literature. Works that consider these issues are surveyed in this paper to provide insight into the state of the art, provide design insights for network designers and motivate future research directions
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